This invention relates generally to helicopter rotor blades and their cross sectional airfoil shape, in particular. The airfoils are particularly suited for use in conjunction with rotors such as those used by helicopters or other types of rotorcraft. The airfoils are designed so as to have maximum lift characteristics at high angle of attack when the blade is retreating and maximum delay in drag rise or drag divergence when the blade is advancing, thus enabling the rotor to counteract the rolling moment which would otherwise be induced by the aircrafts forward flight. This is accomplished while maintaining an airfoil sectional pitching moment coefficient at or about zero so as to enable the blade to impose minimum structural loads on the rotor blade and control system, including the pitch mechanism.